Drawdown and build-up tests are often performed on production and injection wells at regular intervals to monitor the performance of the producing formations in the well. A typical test set-up usually includes a down hole valve (shut in tool) which is placed in the well and manipulated by slick line. There is usually a pressure recording device below the valve which records the pressure response of the formation being tested as the vale is opened or closed. The formation is allowed to flow for a sufficient length of time to insure that it is drawn down to a desired level. After this draw down period is complete, the shut in valve is used to shut in the well. The formation pressure is allowed to build up for a sufficient period of time to allow it to reach a desired level, before another draw down period is started. The entire process is then sometimes repeated immediately to acquire more pressure data from another drawdown/build-up test.
Shut in valves of the prior art have been actuated by mechanical means and electrical means. Mechanical actuators can be lowered on a slickline to operate such valves. Conversely, designs exist which use an electrical motor and controlling circuit to open and close down hole valves.
U.S. Pat. No. 3,587,735 of Owen is an early shut-in tool patent teaching a valve that is mechanical and must be operated, opened and closed, using slick line.
U.S. Pat. No. 5,234,057 owned by the Halliburton Company details the use of an electronic timing circuit and motor to open and close a down hole shut in tool automatically. Not having to use a slick line truck to open and close the valve reduces costs to the service company.
U.S. Pat. No. 6,957,699 owned by Stellar Tech Energy Services Inc. uses a similar timing circuit as Halliburton, this patents details an improved valve apparatus. The valve apparatus uses a ball and seat to seal. The valve also claims a quick close and equalization.
In U.S. Pat. No. 7,114,697 owned by GeoServices, again, an improved valve designed is mentioned. This spring loaded valve has a complicated latch and release mechanism to instantly close and re-open the valve.
Although the present invention is described primarily in the context of down-hole shut-in and injection tools for use within a wellbore, it should be appreciated that the disclosed apparatuses, the methods of use thereof, the valve configurations thereof, the valve drive mechanisms thereof, and related devices used therewith may be used in other applications requiring delivery of a fluid between an interior and exterior of a fluid passage via a pressure difference between the fluid passage and a fluid delivery conduit extending thereinto.